The present invention is related to an alkaline cleaner for removal of greasy soil from hard surface areas. It is especially effective in removing not only the grease but also lime-soaps found in institutional, and commercial kitchens and other food preparation environments. Prior to the present invention, the combination of food greases and lime-soaps have been difficult to clean from hard surfaces such as ceramic floor tiles or countertops. This difficulty apparently is due to unsaturated portions of materials being partially cross-linked which upon aging further polymerize.
Most lime-soap dispersants previously described contain sulfated, sulfonated or phosphonated compounds. Alkyl or alkylaryl ethoxy carboxylates are known in the art as mild surfactants for use in liquid detergent compositions. They have been described as being poor in grease cutting and require the use of other surfactants to achieve the desired cleaning. For example, international patent application, publication number WO92/08777 describes a light-duty dishwashing detergent composition containing an alkyl ethoxy carboxylate surfactant and calcium or magnesium ions and a moderate complexing agent. It was therefore surprising to find that alkyl and alkylaryl ethoxy carboxylates of the present invention are effective in removing greasy soil containing lime-soaps when such active ingredients are combined with a strong chelating agent and a source of alkalinity.
Accordingly the present invention includes an alkaline cleaner for removing greasy soil containing lime-soaps from hard surfaces such as quarry or ceramic floor tiles in commercial and institutional kitchens.
The alkaline cleaner composition comprises:
(1) an effective detersive amount of alkyl or alkylaryl ethoxy carboxylates of the formula
Rxe2x80x94Oxe2x80x94(CH2CH2O)n(CH2)mxe2x80x94CO2X 
wherein R is a C8 to C22 alkyl group or 
in which R1 is a C4-C16 alkyl group,
n is an integer of 1-20,
m is an integer of 1-3, and
X is hydrogen, sodium, potassium, lithium, ammonium, or an amine salt selected from monethanolamine, diethanolamine and triethanolamine;
(2) an effective amount of a strong chelating agent;
(3) an effective amount of a source of alkalinity, and
(4) a diluent.
The cleaner composition can be sold as a concentrate or in the form of a dilute aqueous solution. The concentrate is preferred when sold to restaurants and institutions. Application of the concentrate is then carried out by known dilution methods.
As utilized herein including the claims, the term xe2x80x9cwt %xe2x80x9d refers to the weight proportion based upon the total weight of the composition.
The alkaline cleaner composition may be in solid or liquid form. In liquid form, the composition is preferably sold as a concentrate and used as a dilute aqueous solution. The composition includes an effective detersive amount of an alkyl or alkylaryl ethoxy carboxylate, an effective amount of a chelating agent and an effective amount of a source of alkalinity. The composition also contains a diluent. The diluent for a concentrate may be water, alcohol, or an aqueous alcohol mixture. In dilute form, the diluent is water. The composition may further contain a water conditioning agent and other typical detergent additives such as dyes, perfumes, grease cutting solvents, and the like.
By effective detersive amount is meant an amount of active ingredient required to remove grease and lime-soap dirt from a hard surface.
By an effective amount of a strong chelating agent is meant the amount required to remove the alkaline earth salts (Ca or Mg) from the water hardness used in ordinary cleaning of floor tiles and grouts. The use of chelating agents also help break up the lime-soaps under alkaline conditions and can release soaps that can help in the cleaning process.
By effective amount of a source of alkalinity is meant enough alkaline materials to break apart semi-polymerized soils formed from the fats and lime-soaps which are on hard surfaces, e.g. floor surfaces, through cooking processes. The unsaturated portions of some fats are partially cross-linked and upon aging the soils can be further polymerized. Thus highly alkaline materials such as caustics or strong amines are helpful in breaking these apart.
As a preferred aqueous alkaline cleaning composition, alkyl and alkylaryl ethoxy carboxylates can be present in an amount ranging from about 0.1 to 20 wt %, the strong chelating agent being in the range of about 1-20 wt % and the source of alkalinity being in the range of about 0.5-30 wt %.
More preferred aqueous compositions comprise:
(1) about 1-5 wt % of alkyl or alkylaryl ethoxy carboxylate;
(2) about 10-15 wt % of a strong chelating agent, and
(3) about 2-12 wt % of a source of alkalinity.
The source of alkalinity is normally higher in the above range when the composition is used for commercial and institutional kitchen floors. Since the composition is useful for cleaning ceramic surfaces, the composition may also be applied in diluted form in cleaning household bathroom tiles as well as bathroom tiles in commercial locations. In this aspect, the percentage of source of alkalinity would be closer to the bottom of the above range, e.g. on or about the 2% level.
Preferred alkyl or alkylaryl ethoxy carboxylates of the above formula are those where n is an integer of 4 to 10 and m is 1.
Also preferred carboxylates are those alkyl carboxylates where R is a C8-C16 alkyl group. Most preferred of the alkyl ethoxy carboxylates are those where R is a C12-C14 alkyl group, n is 4 and m is 1.
In the alkylaryl series, a preferred embodiment is where R is of the formula 
in which R1 is a C6-C12 alkyl group. Most preferred is a carboxylate where R1 is a C9 alkyl group, n is 10 and m is 1.
The alkyl and alkylaryl carboxylates may be purchased as surfactants from commercial stores. Alternatively, they can be made by known synthetic methods starting with a fatty alcohol in the alkyl ethoxy carboxylate series. This fatty alcohol can be monitorily reacted with ethylene oxide to prepare the required number of ethoxy linkages. The resulting ethoxy alcohol is then further reacted with a halo carboxylic acid such as, for example, halo-acetic acid, halo-propionic acid or halo-butyric acid to form the desired carboxylate.
In the alkylaryl series, an alkylated phenol can be reacted in the same manner with ethylene oxide and further with the halo carboxylic acid to form the desired carboxylate.
As an example of commercially available carboxylates, Emcol CLA-40, a C12-14 alkyl polyethoxy (4) carboxylic acid, and Emcol CNP-110, a C9 alkylaryl polyethoxy (10) carboxylic acid are available from Witco Chemical. Carboxylates are also available from Sandoz, e.g. the product Sandopan(copyright) DTC, a C13 alkyl polyethoxy (7) carboxylic acid.
The second active component in the alkaline cleaner composition is a strong chelating agent preferably in the form of its alkaline metal salt such as potassium or preferably the sodium salt. Chelating or sequestering agents are those molecules capable of coordinating the metal ions commonly found in hard water and thereby preventing the metal ions, eg. Ca and Mg, from interfering with the functioning of the detersive component of the composition. Strong chelating agents are aminopolycarboxylic acids such as, for example, nitrilotriacetic acid (NTA), ethylenediamine tetracetic acid (EDTA), N-hydroxyethyl-ethylenediamine triacetic acid (HEDTA), and diethylene-triamine pentaacetic acid (DTPA). The preferred chelating agent is ethylenediamine tetracetic acid (EDTA) in the form of its tetrasodium salt.
The third active component of the present alkaline cleaner composition is a source of alkalinity which can be an organic source or an inorganic source. Organic sources of alkalinity are often strong nitrogen bases including, for example, ammonia (ammonium hydroxide), monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine, triethanolamine, tripropanolamine, and the like.
The inorganic alkaline source contained in the alkaline cleaners of this invention is preferably derived from sodium or potassium hydroxide. The preferred form is commercially available sodium hydroxide, which can be obtained in aqueous solution of concentrations of about 50 wt %.
As preferred sources of alkalinity, ammonia or ammonium hydroxide, monoethanolamine and sodium hydroxide in 50 wt % aqueous solution is preferred. Most preferred is a combination of the three.
The composition of the present invention is manufactured in either a concentrate formulation or dilute aqueous formulation. All formulations are prepared initially in concentrated form by combining the ingredients in a mixing vessel and mixing the components creating a homogeneous liquid composition.
The resulting concentrate may be diluted and bottled for household purposes for cleaning bathroom tiles.
Preferably, the concentrate is sold as such for institutional and commercial settings which require a significant amount of the compositions. The purchased concentrated composition is then diluted to the proper strength at the site where they will be used. Systems for diluting concentrates are well known in the art and are normally employed by a wide variety of users, e.g. hotels, hospitals, restaurants, etc. Dispensing systems may cover a wide range in terms of complexity. The method of dilution may be rather simple and manual or require operator experience. A preferred method for dispensing a concentrate is described in U.S. Pat. No. 5,033,649 which is incorporated herein by reference. The solution storage and dispensing apparatus has a container with two inlet ports for two different types of liquid e.g. a water and the liquid cleaning concentrate. The inlet ports for the two different types of liquid accommodate two inlet lines which transport the liquid into the container. The inlet lines are each removably interconnected to their respective liquid sources and container inlet ports. The container has a suitable proportioning means, such as an aspirator, permanently mounted inside of it.
The following examples illustrate in more detail the present invention but are not limiting thereon. The alkaline cleaner compositions of the present invention were compared with other known surfactants. The data demonstrated the superiority of the present compositions in removing soil containing grease and lime-soaps from hard surfaces such as found in commercial and institutional kitchen floors.